The research team evaluated the efficacy of certolizumab pegol in 662 adults with moderate-to-severe Crohn's disease.

Patients were stratified according to baseline levels of C-reactive protein (CRP).

The patients were randomly assigned to receive either 400 mg of certolizumab pegol or placebo subcutaneously at weeks 0, 2, and 4 and then every 4 weeks.

Primary end points were the induction of a response at week 6 and a response at both weeks 6 and 26.

37% in the certolizumab group had a response at week 6

New England Journal of Medicine

Among patients with a baseline C-reactive protein level of at least 10 mg per liter, 37% of patients in the certolizumab group had a response at week 6.

The team found that 26% in the placebo group had a response at week 6.

At both weeks 6 and 26, the corresponding values were 22% and 12%, respectively.

In the overall population, the researchers noted that the response rates at week 6 were 35% in the certolizumab group, and 27% in the placebo group.

At both weeks 6 and 26, the response rates were 23% and 16%, respectively, in the general population.

At weeks 6 and 26, the team observed that rates of remission in the 2 groups did not differ significantly.

Serious adverse events were reported in 10% of patients in the certolizumab group and 7% of those in the placebo group.

The team reported serious infections in 2% and less than 1%, in the certolizumab and placebo group, respectively.

In the certolizumab group, antibodies to the drug developed in 8% of patients, and antinuclear antibodies developed in 2%.

Dr Sandborn's team concludes, "In patients with moderate-to-severe Crohn's disease, induction and maintenance therapy with certolizumab pegol was associated with a modest improvement in response rates, as compared with placebo, but with no significant improvement in remission rates."